Feasible method of cracking long, randomised passwords?

[CracktainCrunch]

It would essentially be a brute force attack but with pre-generated passwords that one would use in a dict attack I guess.

I'm not sure what brought this idea. You want the worst of both worlds? The way too large keyspace of a brute-force attack paired with the slightly slower speed of a dictionary attack? If you want to do a brute-force you should use the mask attack. But if your passwords exceeds 7 or 8 characters (leave alone 10 do 15) this pretty much is infeasible. You need clever attacks like dict+rules.

There seems to be a misunderstanding I guess. I am new to all of this so I am not sure if I expressed myself correctly.
Since I don't know the password and have not the slightest idea how it was generated - it's an encrypted archive that I downloaded from usenet but don't remember which board provided the NZB and they all have passwords like "QTSQfy9VVpHaRdcDY%" - I am assuming it is between 10 and 15 characters long consisting of lower, upper case letters, numbers and special signs like %. I understand that anything larger than 8 characters is infeasible to use brute force on, even with a mask. So I wondered if it would help to shorten the time by generating a bunch of random passwords that are 10 to 15 characters in length containing lower, upper case letters, numbers and special signs since hashcat wouldn't have to do that on the fly, copy them into a wordlist and use that wordlist to attack the archive.
That is just an idea, I have no clue if it makes sense speed wise. That's why I decided to ask?